Batteries

[riley]

How do batteries work?

[CrankSPL]

One "end" or "terminal" (or node or electrode) is made of a substance that pulls electrons chemically from the ("electrolyte solution") substance in the battery, and the other terminal is made of a substance which gets the electrons pulled from it, into the substance inside the battery. So, chemically, it causes a current from one terminal in the battery (the one that pulls the electrons away from the stuff in the battery), through a circuit (a radio, a car, a light, or whatever), and then as if back around through the battery again, until it runs out of the "charges" ("positive" and "negative") that the substance inside has.

[Sensei]

A battery consists of two dissimilar metals, separated by an electrolyte (acid). A chemical reaction causes an excess of electrons on one side (the negative side) and an absence of electrons on the positive side. When you hook a battery to something, say a light bulb, the electrons can travel from the negative side where there is an excess to the positive side where there is a deficit. The battery dies when there is no difference in the number of electrons between the pos & neg sides.